What was an effect of nationalism in Europe during the early 1900s?


Countries decided to adopt a common language.


Alliances between groups of nations led to World War I.


Countries formed a union to protect European political interests.


Countries learned to work together for the good of all Europe.

3 answers

How is this mathematics?

I would got with WWI.
This is not Maths whatsoever.
oops, sorry, I pressed the wrong one, my bad.